1. Field of the Invention
This invention relates generally to tire retreading and more specifically, to buffing machines for buffing tread from a crown of the tire.
2. Description of the Related Art
Tires are known to comprise a tread consisting of an outer layer of rubber-based mixtures, of greater or lesser thickness, in which are molded various grooves and tread patterns intended, inter alia, to improve the vehicle's grip relative to the ground. A tire may also include undertread, which is similar in composition to tread material and is generally located between the tread and the belt.
In certain cases, it is necessary to machine or remove at least a portion of the outer surface of the tire, such as, for example, the tire tread and undertread, for the purpose of preparing a worn tire for retreading. Typically, the removal process has been accomplished by a machine containing a buffing head, the buffing head being one of various types of abrading devices, such as rasps, grinding wheels, and wire brushes. The removal process may also be achieved by a cutting process that utilizes a cylindrical cutter called a “peeler.”
During the removal process, it may be desirable to monitor the amount of material remaining above the belt so that the removal device does not contact or damage the belt, which, if occurring would destroy the tire. Therefore, removal devices may use various types of sensors to monitor the amount of material remaining above the belt during the removal process. Such sensors are well known to those having ordinary skill in the art and an example of one is fully disclosed in U.S. Pat. No. 6,386,024, which is hereby fully incorporated by reference.
Generally, variations in tread and/or undertread thickness may result in tire imbalance or other degradation in tire performance or quality. To avoid any such impairment, it may be advantageous to determine whether the thickness of the material remaining above the tire belt (i.e., the “buffed crown layer”) contains any variations. Therefore, it may be desirable to measure the buffed crown layer after the removal of material to ascertain any variations in material thickness about the tire, and to correct any such variations.